Field of the Invention
The present invention relates to a lamination molding device.
Background of the Invention
In a powder sintering/laminating method (laser lithography) of metal using laser beam, a particular smoke known as fume is generated when the metal material powder is irradiated with laser beam for sintering.
Current laser lithography apparatus (sintering lamination molding apparatus) for molding metal products is generally operated by supplying the material powder in a chamber filled with inert gas (usually nitrogen gas), followed by irradiation of the material powder with the laser beam.
When the chamber gets filled with fume, the fume may shield the laser beam, and the laser beam with necessary energy may not reach the sintering portion. Therefore, clean inert gas is continuously supplied into the chamber while the contaminated inert gas is exhausted out of the chamber (Patent Literature 1).
The fume is generated at the sintering portion, and then rises so as to cover the periphery of the sintering portion. Here, the sintering portion is irradiated with the laser beam which is generally provided from substantially the upper side in vertical direction. In such case, the fume gets in the optical pathway of the laser beam. Therefore, the fume may not be removed sufficiently when the inert gas in the chamber is merely circulated. Accordingly, a method for exhausting the inert gas in the chamber by leading the fume away from the optical pathway by utilizing the supplying opening and the exhausting opening of the inert gas has been suggested (Patent Literature 2).